build: check compilation of each commit

Inspired by Rust Lightning's GH action :)

.github/workflows/main.yml

@@ -63,14 +63,16 @@ jobs:
         run: make rpc-check
 
   ########################
-  # compile unit tests
+  # check commits
   ########################
-  unit-compile:
-    name: compile unit tests
+  check-commits:
+    name: check commits
     runs-on: ubuntu-latest
     steps:
       - name: git checkout
         uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
 
       - name: go cache
         uses: actions/cache@v1
@@ -88,8 +90,16 @@ jobs:
         with:
           go-version: '~${{ env.GO_VERSION }}'
 
-      - name: compile
-        run: make unit pkg=... case=_NONE_
+      - name: fetch and rebase on master
+        run: |
+          git remote add upstream https://github.com/lightningnetwork/lnd
+          git fetch upstream
+          export GIT_COMMITTER_EMAIL="lnd-ci@example.com"
+          export GIT_COMMITTER_NAME="LND CI"
+          git rebase upstream/master
+
+      - name: check commits
+        run: scripts/check-each-commit.sh upstream/master
 
   ########################
   # lint code

scripts/check-commit.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+set -e
+set -x
+echo Testing $(git log -1 --oneline)
+make unit pkg=... case=_NONE_

scripts/check-each-commit.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+if [[ "$1" = "" ]]; then
+	echo "USAGE: $0 remote/head_branch"
+	echo "eg $0 upstream/master"
+	exit 1
+fi
+
+set -e
+set -x
+
+if [[ "$(git log --pretty="%H %D" | grep "^[0-9a-f]*.* $1")" = "" ]]; then
+	echo "It seems like the current checked-out commit is not based on $1"
+	exit 1
+fi
+git rebase --exec scripts/check-commit.sh $1